Wire-tying machine



March 17, 1959 H. K. EMBREE 2,877,898

WIRE-TYING MACHINE Filed Jung 2, 1955 United States aten WIRE-TYING MACHINE Harold K. Embree, Hamilton, Ontario, Canada, assignor to Ovalstrapping Inc., Hoquiam, Wash, a corporation of Washington Application June 2, 1955, Serial No. 512,831

6 Claims. (Cl. 14093.6)

This invention relates generally to a wire-tying machine having an improved cut-off mechanism for cutting the reel end of the wire after completion of the twisting of the wire by the machine to form a conventional wire tie.

In wire-tying machines which form the tie by twisting action it is desirable to have the wire cutting step automatically efiected towards the end of the movement given to the well-known twister pinion. It is also desirable to give a small amount of overtwist to the tied wire, for reasons well-known to those familiar with the wiretying or strapping art. The desired automatically efiected wire-cutting step should be timed to occur as the twisting step proper is completed and just as the overtwisting step begins; and the cutting step should be followed closely by automatic return of the cutting element to its initial position.

While these desiderata may be stated in a few words, the mechanics of their accomplishment has been considered complex; and the art has lacked a mechanically simple arrangement for automatically effecting the desired cutting of the wire at the desired moment. After considerable study and experiment I have developed an extremely simple and satisfactory wire cut-ofi? mechanism.

Since the operation of my novel wire-cutting mechanism ,is initiated and controlled by the operation of the drive for the twister pinion, it appears that any complete definition, of the invention must refer to said drive as well as to the cut-off mechanism proper. Working on this assumption, the clearest definition of the essential features of the invention which I have been able to devise reads as follows: A wire-tying machine comprising a gear housing: a wire-twisting pinion rotatably mounted within said housing: gearing for unidirectionally driving said pinion mounted within said housing: means for driving said gearing: and a wire cut-off mechanism mounted on one side of said housing, said cut-off mechanism comprising a wire cut-oft lever pivotally mounted on one side of said housing, said lever carrying a wire-cutting edge and being pivotally mounted on said housing at a point remote from said cutting edge; biasing means urging said lever upwardly so that said cutting-edge is normally located above and out of contact with the wire to be cut; stop means limiting the upward movement of said lever; and means for positively forcing said lever downward against the action of said biasing means to bring said cutting edge into cutting engagement with the wire, said forcing means comprising a camshaft projecting from said housing at right angles to the longitudinal axis of said lever, said camshaft being operatively connected to said gearing which unidirectionally drives said pinion, a cam loosely mounted on said camshaft at a point above said lever, a key and a keyway providing driving connection between said camshaft and said cam, said keyway being appreciably wider than said key so that a lost motion is-provided in the driving of said camby the camshaft.

In drawings which illustrate a presently preferred embodiment of the invention:

Figure 1 is a front elevational view with part of the wire-tying machine detached and moved over to the righthand side of the drawing, the better to show the drive mechanism,

Figure 2 is a sectional view taken along the line 2--2 in Figure l, and

Figure 3 is a view showing, on a comparatively generous scale, the cam and the manner of its mounting on the camshaft.

The illustrated wire-tying machine consists of three main parts, namely a central part A containing the driving mechanism 10 for the twister pinion 11; an end section B carrying a wire-end gripping mechanism 12, which forms no part of the present invention; and an opposite end section C carrying a wire-tensioning mechanism 13, which is also outside the scope of the present invention.

The driving mechanism 10 is mounted in a housing 14, which is separable into two parts 14A and 14B for assembly, maintenance, etc. This separation has been effected in the case of Figure 1 in order that the invention may be adequately illustrated.

While the invention is applicable both to hand-operated or power-driven machines, a hand-operated machine has been selected for purposes of illustration. The machine is operated by grasping one of, or preferably both of, the two operating levers 15A and 15B, and swinging the levers in the direction of the arrows 16 so that they pass one another. Lever 15A is the true operating lever since it is rigidly connected to a rotatable drive-shaft 17 which operates the driving mechanism 10. Operating lever 15B is rigidly attached to a stub shaft 18 which is rotatably mounted in, and extends rearwardly from, housing 14. Actuation of either of the levers will actuate the drive mechanism 10, however, since the lower end of each lever is provided with an arcuate toothed segment, the teeth of the segment of one lever meshing with those of the other.

Gearing for unidirectionally driving the twister pinion 11 is mounted within the housing 14. This gearing consists of (A) a bevel gear 19 carried by drive-shaft 17' and operatively connected thereto by a one-way clutch 20, (B) a bevel gear 21, meshing with bevel gear 19, and rigidly mounted on a shaft 22 which is rotatably mounted within the housing at right angles to the driveshaft 1'7; and (C) a second gear 23 carried by shaft 22. Gear 23 is rigidly secured to shaft 22 and meshes with the twister pinion 11. The gearing, on the basis of wellknown calculating procedures, is worked out to drive the twister pinion 11 a multiple of 360 degrees plus a minor fraction of an additional revolution, for each full operative swing of the operating lever 15A. The minor fraction of the additional revolution is of course intended to give the desired overtwist, and no particular fraction is being named since the fraction will necessarily vary with the characteristics of the tying wire a given machine is primarily designed to handle. Suitable stops are, of course, provided to impose limitations upon the movement of the levers 15A and 15B in the direction of the arrows 16, and in the opposite directions. The movement of the operating levers 15A and 153 in the directions of arrows 16 imparts movement to bevel gear 19 through driving engagement thereof by the one-way clutch 20. Movement of the levers in the opposite directions disengages clutch 20 and frees gears 19, 21 and 23 together with shaft 22 and twister pinion 11.

The freeing of the twister pinion 11 permits the latter to rotate from its overtwisted position, wherein the wirereceiving recess 11A of the pinion is incorrectly located for the withdrawal of the tied wire from said recess and the insertion of new portions of wire requiring tying, to the correct position, i. e. one in which the recess is horizontally disposed in proper alignment with the usual wireretaining channel 24. The pinion 11 is caused to rotate towards this correct position, i. e. rotate in a direction opposite to that in which it was driven during the twisting and overtwisting of the wire, by a reaction to the twisting action established in the wire itself in the region of the tie. Moveover the pinion is urged towards its position of proper alignment, and is eventually seized and held in said position, by the action of a spring-loaded pawl entering one of a plurality of notches located at equally spaced intervals in a plate carried by shaft 22 in the region thereof which is obscured by housing part 14A. The notches are shaped to minimize interference by the spring-loaded pawl when the plate, shaft 22, and gears 21 and 23 are being driven by the shaft 17, and to encourage interference and locking by the spring-loaded pawl when the said plate, shaft and gears are being driven in the opposite direction by the twister pinion 11. It has not been felt necessary to illustrate the springloaded pawl and the notched plate since this arrangement has already been widely used in the art as a solution to the problem of properly aligning overtwisted twister pinions. It was, however, felt necessary to provide this brief discussion in order to delineate the fact that there is rotation of each of the twister pinion 11, the gear 23 meshing therewith, the shaft 22 and gears 21 and 19, in the direction opposite to that in which each of said elements is driven when gear 19 is engaged by the clutch associated with the drive-shaft 17. The amount of this reverse rotation will, in the case of each element, be a direct function of the amount of overtwist imparted to the twister pinion 11.

Turning now to the cut-off mechanism proper, as best seen in Figure 2 a wire cut-01f lever 25 is pivotally mounted at 25A on the side of housing part 14A. The cut-off lever 25 is biased upwardly by a spring-loaded element 26 mounted in the base of the machine below the lever; and upward movement of the lever is limited by a stop means 27 connected to said base. Lever 25 carries, at the end thereof remote from its point of pivotal mounting 25A, a cutting edge 28 which is disposed immediately adjacent the end of the wire-retaining channel 24 and is normally held somewhat thereabove by the springloaded element 26 pressing the lever 25 against the stop means 27. Means are provided for positively forcing the lever 25 downward, against the action of spring-loaded element 26, whereby the cutting edge 28 will be caused to swing down across the end of channel 24 to effect cutting of one of the courses of the wire passing therethrough.

This means for forcing the lever downward to effect the cut comprises a camshaft 29 and a cam 30 loosely mounted thereon at a point vertically above the lever 25. Camshaft 29 extends outwardly from housing part 14A, wherein it is rotatably mounted. The camshaft is located above cut-off lever 25 and is disposed at right angles to the longitudinal axis of said lever. The camshaft is preferably an integral extension of shaft 22, but if the two are not integrally formed, the camshaft 29 should be rigidly connected to shaft 22 so as to rotate with the latter.

The cam 30 is a generally annular block centrally bored for rotatable mounting on the camshaft. Lateral displacement of the cam on the camshaft is prevented by providing the camshaft with a shoulder adjacent its end and a plate 31 removably secured to the end face of the camshaft by means of screws 32 (see Figure 2) which enter axial screw-threaded holes 32A provided in the end portion of the camshaft (see Figure 3, wherein the plate 31 has been removed). The central bore in the cam is cut away to provide a keyway 33 (see Figure 3) and a key 33A is mounted in a channel 33B cut in the outer end of the camshaft. While the key 33A enters the keyway 33 so that the cam 30 will be driven by the keyed camshaft 29, attention is drawn to the fact that the keyway 33 is appreciably wider than the key 33)! whereby lost motion is provided in the driving of the cam by the camshaft. The need for this lost motion will appear later on in the description.

The exterior surface of the annular block constituting the cam 30 is provided with two similar camming surfaces 34 which extend tangentially from the surface of the block at points spaced degrees apart, each of said camming surfaces terminating sharply in a step formation 35, the steps 35 also being spaced 180 degrees apart from one another. The upper surface of the cut-off lever 25 is cut away in the region contacted by the cam 30 to provide a step formation 36 arranged to cooperate with one of the steps 35 on the cam and prevent rotation of the latter in the direction of arrow A (Figure 2) when the steps are in abutting relation.

It was mentioned earlier that each complete operative swing of the levers 15A and 153 causes twister pinion 11 to rotate through a multiple of 360 degrees plus a minor fraction of an additional revolution. The complete operative swing also causes shaft 22 and the camshaft 29 to rotate through 180 degrees plus a minor fraction of a complete revolution. It will be realized that the two minor fractions mentioned in the preceding sentences are necessary for the production of the desired overtwist. It will also be realized that the camming surfaces 34 are intended to force cut-oh lever 25 downward as the cam 30 is rotated in the direction of arrow B by means of the keyed camshaft 29 (which in turn is actuated by levers 15A and 158 through drive mechanism 10). The positive downward force alternately caused by each of the two camming surfaces 34 brings about cutting of the wire by edge 28 just prior to the imparting of overtwist to the tied wire since, in the initial position, the step 35 of the camming surface which is to next force the lever downward is located directly above the step 36 in the cut-off lever 25, while the other cam step 35 abuts step 36. The provision of the two camming surfaces 34 with steps spaced 180 degrees apart may at first appear inconsistent with the fact that camshaft 29 is, with each complete operative swing of levers 15A and 15B, driven through somewhat more than 180 degrees. The answer to this seeming inconsistency resides in the lost motion provided in the driving of the cam by having the keyway 33 of appreciably greater width than the key 33A carried by the camshaft.

While it is believed that the operation of the machine will be clear from what has already been said, the tying of a package with the illustrated machine will now be described. The machine is placed upon the package which is to be tied, tying wire is drawn off a supply reel and caused to encircle the package, and the free end of the wire is passed through channel 24 and recess 11A of twister pinion 11, the extreme free end being finally inserted and secured in gripping mechanism 12. A further course of the wire is passed through channel 24 and recess 11A, and inserted in tensioning mechanism 13, so that two courses of wire extend beside one another through channel 24, one course ending in the gripping mechanism 12 and the other extending via tensioning mechanism 13 to the supply reel. The wire is now tensioned, and the tensioned wire is twisted by moving levers 15A and 15B in the direction of arrows 16. The levers should be swung as far as their stops permit, i. e. they should be given a complete operative swing. Such action, as already indicated, twists and overtwists the two courses of wire passing through the recess 11A of twister pinion 11, by rotating shafts 17 and 22. As the twisting proceeds, the camming surface 34 which was uppermost at the beginning of twisting starts forcing. lever 25 downward, eventually forcing cutting edge 28 through the course of wire leading to the supply reel. The cut is completed by the end of the twisting action, and, while the overtwisting step occurs, the step 35 (of the camming surface which actuated the lever 25) passes step 36 on the cut-off lever, thereby permitting the lever 25 to rise out of its cutting position under the influence of the spring-loaded element 26.

The operating levers would now be swung back to their original positions, and while such action necessarily entails rotation of drive-shaft 17, the drive mechanism is freed by the one-way clutch 20. The gearing, together with shaft and the camshaft will be given a small amount of reverse rotation, despite the disengagement of clutch 20, as pointed out earlier. The cam 30 will not, however, participate in this reverse rotation because one of the steps 35 on the cam will be held by the step 36 on the cut-off lever, the camshaft being permitted limited motion relative to the cam by virtue of the width of the keyway 33as compared to that of the key 33A.

It will be appreciated that the excess width of keyway required will vary as a direct function of the degree of overtwist featured; by any particular machine. Tobe more specific, if one complete operative swingof operating levers A- and 15B imparts three twisting revolutions and 30 degrees of overtwist to the twister pinion 11, i. e. rotatesit through 1110 degrees; and the gear ratio between the twister pinion and the gear 23 (which controls the degree of rotation of camshaft 29) is 6:1 so that gear 23 is given somewhat more than 180 degrees rotation per operative swing; then the excess width of the keyway should be sufiicient to permit 30+6=5 degrees of revolution of the cam relative to the camshaft.

I claim:

1. A wire-tying machine comprising a gear housing: a wire-twisting pinion rotatably mounted within said housing: gearing for unidirectionally driving said pinion mounted within said housing: means for driving said gearing and adapted to impart therethrough to said pinion, upon operation of the means for driving said gearing, a rotation of a multiple of 360 degrees plus a minor fraction of an additional revolution whereby to impart the desired twist to the wire plus the desired amount of overtwist: and a wire cut-off mechanism mounted on one side of said housing, said cut-off mechanism comprising a wire cut-off lever pivotally mounted on one side of said housing, said lever carrying a wire-cutting edge and being pivotally mounted on said housing at a point remote from said cutting edge; biasing means urging said lever upwardly so that said cutting-edge is normally located above and out of contact with the wire to be cut; stop means limiting the upward movement of said lever; and means for positively forcing said lever downward against the action of said biasing means to bring said cutting edge into cutting engagement with the wire during twisting, said forcing means comprising a camshaft projecting from said housing at right angles to the longitudinal axis of said lever, said camshaft being operatively connected to said gearing which unidirectionally drives said pinion and adapted to be rotated upon operation of the means for driving the gearing through the required angular distance including a related fraction of a revolution to that imparted to the said pinion, a cam loosely mounted on said camshaft at a point above said lever, a key and a keyway providing driving connection between said camshaft and said cam, said keyway being appreciably wider than said key so that a lost motion is provided in the driving of said cam by the camshaft whereby said camshaft is rotated together with said gearing through a sufficient arc to permit said pinion to impart the full twist to the wire and to complete the cutting by the end of wire twisting and before overtwisting.

2. A wire-tying machine as defined in claim 1 in which said biasing means is a spring-loaded element mounted in the machine below said lever.

3. A wire-tying machine as defined in claim 1, in which said means for driving said gearing comprises a drive-shaft and an operating lever for rotating said driveshaft rigidly secured thereto and extending therefrom at right angles, a second lever mounted on a stub shaft rotatably mounted and extending rearwardly from saidgear housing, said levers being operatively, connected together at their lower ends so that movement of one lever is transmitted to the other and in which said gearing includes a pair of gears set at right angles to one another, whereby said twister pinion is rendered rotatable about an axis which lies at right angles to the axis of rotation of said drive-shaft.

4. A wire-tying machine as defined in claim 1, in which said means for driving said gearing comprises a driveshaft, an operating lever for rotating said drive-shaft, and a one-way clutch connection between said drive-shaft and said gearing for unidirectionally driving said twister pinion; and in which said pinion is driven through a multiple of 360 degrees plus a minor fraction of an additional revolution with each full operative swing of the operating lever.

5. A wire-tying machine comprising a gear housing: a, wire-twisting pinion rotatably mounted within said housing: gearing for unidirectionally driving said pinion mounted within said housing: means for driving said gearing and adapted to impart therethrough to said pinion, upon operation of themeans for driving said gearing, a rotation of a multiple of 360 degrees plus a minor fraction of an additional revolution whereby to impart the desired twist to the wire plus the desired amount of overtwist: and a wire cut-off mechanism mounted on one side of said housing, said cut-01f mechanism comprising a wire cut-off lever pivotally mounted on one side of said housing, said lever carrying a wirecutting edge and being pivotally mounted on said housing at a point remote from said cutting edge; biasing means urging said lever upwardly so that said cutting-edge is normally located above and out of contact with the wire to be cut; stop means limiting the upward movement of said lever; and means for positively forcing said lever downward against the action of said biasing means to bring said cutting edge into cutting engagement with the wire during twisting, said forcing means comprising a camshaft projecting from said housing at right angles to the longitudinal axis of said lever, said camshaft being operatively connected to said gearing which unidirectionally drives said pinion and adapted to be rotated upon operation of the means for driving the gearing through the required angular distance including a related fraction of a revolution to that imparted to the said pinion, a cam loosely mounted on said camshaft at a point above said lever, said cam comprising a generally annular block circularly bored for rotatable mounting on said camshaft, the exterior surface of the block being generally concentric with said bore but having at least one camming surface which extends tangentially outwardly from a point on the generally concentric portion and terminates sharply in a step formation; and in which the upper surface of said cut-ofl lever is cut away in the region contacted by said cam to provide a definite step formation, a key and a keyway providing driving connection between said camshaft and said cam, said keyway being appreciably wider than said key so that a lost motion is provided in the driving of said cam by the camshaft whereby said camshaft is rotated together with said gearing through a sufficient arc to permit said pinion to impart the full twist to the wire and to complete the cutting by the end of wire twisting and before overtwisting.

6. A wire-tying machine comprising a gear housing: a wire-twisting pinion rotatably mounted within said housing: gearing for unidirectionally driving said pinion mounted within said housing: means for driving said gearing and adapted to impart therethrough to said pinion, upon operation of the means for driving said gearing, a rotation of a multiple of 360 degrees plus a minor fraction of an additional revolution whereby to impart the desired twist to the wire plus the desired amount of overtwist: and a wire cut-off mechanism mounted on one side of said housing, said cut-off mechanism comprising a wire cut-off lever pivotally mounted on one side of said housing, said lever carrying a wirecutting edge and being pivotally mounted on said housing at a point remote from said cutting edge; biasing means urging said lever upwardly so that said cuttingedge is normally located above and out of contact with the wire to be cut; stop means limiting the upward movement of said lever; and means for positively forcing said lever downward against the action of said biasing means to bring said cutting edge into cutting engagement with the wire during twisting, said forcing means comprising a camshaft projecting from said housing at right angles to the longitudinal axis of said lever, said camshaft being operatively connected to said gearing which unidirectionally drives said pinion and adapted to be rotated through 180 degrees upon operation of the means for driving the gearing, a cam loosely mounted on said shaft at a point above said lever, which cam comprises a generally annular block circularly bored for rotatable mounting on said camshaft, the exterior surface of the block being generally concentric with said bore but having two diametrically opposite camming surfaces which extend tangentially outwardly from a point on the gen-' erally concentric portion and terminate sharply each in a step formation; and in which the upper surface of said cut-off lever is cut away in the region contacted by said cam to provide a definite step formation, a key and a keyway providing driving connection between said camshaft and said cam, said keyway being appreciably wider than said key so that a lost motion is provided in the driving of said cam by the camshaft whereby said camshaft is rotated together with said gearing through a sufficient arc to permit said pinion to impart the full twist to the wire and to complete the cutting by the end of wire twisting and before overtwisting.

References Cited in the file of this patent UNITED STATES PATENTS 1,689,904 Wood Oct. 30, 1928 1,814,188 Rietmann et al. July 14, 1931 1,821,389 McChesney Sept. 1, 1931 1,970,589 Wright Aug. 21, 1934 2,033,581 Malinge Mar. 10, 1936 2,247,776 Gerrard July 1, 1941 2,422,643 Kamper June 17 1947 

